RULE 68. OFFER OF JUDGMENT.
At any time more than 10 days before the trial begins, a party defending against a claim may serve upon the adverse party an offer to allow judgment to be taken against him for the money or property, or to the effect specified in his offer, with costs then accrued. Likewise a party prosecuting a claim may serve upon the adverse party an offer to allow judgment to be taken against that adverse party for the money or property or to the effect specified in his offer with costs then accrued. If within 10 days after service of the offer the adverse party serves written notice that the offer is accepted, either party may file the offer and notice of acceptance, together with proof of service thereof, with the court and thereupon judgment shall be rendered accordingly. An offer not accepted shall be deemed withdrawn and evidence thereof is not admissible except in the proceeding to determine costs. If the judgment finally obtained by the offeree is not more favorable than the offer, the offeree shall pay all costs accruing after the making of the offer. The fact that an offer is made but not accepted does not preclude a subsequent offer.